Combined Effects of Surface Charge and Pore Size on Co-Enhanced Permeability and Ion Selectivity through RGO-OCNT Nanofiltration Membranes

2018 ◽  
Vol 52 (8) ◽  
pp. 4827-4834 ◽  
Author(s):  
Haiguang Zhang ◽  
Xie Quan ◽  
Shuo Chen ◽  
Xinfei Fan ◽  
Gaoliang Wei ◽  
...  
Keyword(s):  
Surface Charge ◽  
Pore Size ◽  
Ion Selectivity ◽  
Combined Effects ◽  
Nanofiltration Membranes

Nanofiltration membranes with narrowed pore size distribution via pore wall modification

2016 ◽  
Vol 52 (55) ◽  
pp. 8589-8592 ◽  
Author(s):  
Yong Du ◽  
Yan Lv ◽  
Wen-Ze Qiu ◽  
Jian Wu ◽  
Zhi-Kang Xu
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Pore Wall ◽  
Nanofiltration Membranes ◽  
Novel Method

A novel method has been proposed to modify the pore wall of nanofiltration membranes (NFMs) by filtrating molecules that are reactive to the NFMs, leading to narrowed pore size distribution.

Pore size and surface charge control in mesoporous TiO2 using post-grafted SAMs

2010 ◽  
Vol 12 (7) ◽  
pp. 1473 ◽  
Author(s):  
Dereje Hailu Taffa ◽  
Murugavel Kathiresan ◽  
Lorenz Walder ◽  
Britta Seelandt ◽  
Michael Wark
Keyword(s):  
Surface Charge ◽  
Pore Size ◽  
Mesoporous Tio2 ◽  
Charge Control

scholarly journals Advancement of Measurement Techniques for Tunable Resistive Pulse Sensing

2021 ◽  
Author(s):  
◽  
Eva Weatherall
Keyword(s):  
Surface Charge ◽  
Pore Size ◽  
Applied Voltage ◽  
Particle Surface ◽  
Streaming Potential ◽  
Pore Surface ◽  
Size Distributions ◽  
Ζ Potential ◽  
Resistive Pulse ◽  
Tunable Resistive Pulse Sensing

<p>Tunable resistive pulse sensing (TRPS) is a particle-by-particle analysis technique combining the Coulter principle with size-tunable pores. TRPS can be used to characterize biological and synthetic particles 50 nm - 20 µm in diameter. Information is obtained from the resistive pulse signal, a transient change in ionic current observed when a particle passes through the pore. TRPS has been shown to provide excellent resolution and accuracy for measuring particle size and concentration as well as providing information about particle charge. TRPS is therefore applicable to many industrial and fundamental research areas involving aptamers, drug delivery particles, extracellular vesicles and other biological particle types. Advancement of this technology requires a better understanding of the technique, particularly in the area of particle surface charge measurement and this Thesis helps to provide that understanding.  In this work, firstly particle ζ-potential measurement using TRPS was investigated. A number of different measurement methods are presented and the uncertainties associated with each method are outlined. The ζ-potential for a variety of particles with different surface charges were measured in a range of electrolytes.  Particle ζ-potential measurements were then improved upon with the addition of streaming potential measurements to measure the pore surface charge. The ζ-potential of the pore surface, which makes a significant contribution to particle ζ-potential calculations, was measured using a set up which works alongside the qNano. Streaming potential measurements were also used to investigate changes in the pore surface charge following application of number of different chemical coatings. The volume of data collected and detail of analysis in this work (including uncertainties) is unprecedented in TRPS ζ potential measurements.  Biphasic pulses arising from the charge on the particles were investigated. The pulse is conventionally resistive, but biphasic pulses which include both resistive and conductive components are significant for less than 50 mM salt concentrations when measuring 200 nm particles. The experimental variables investigated include the concentration of the electrolyte, particle charge, pore size, applied voltage, and the direction of particlemotion. Conductive pulse size was seen to decrease with increasing electrolyte concentration and pore size and increase with applied voltage. A linear relationship was found between conductive pulse magnitude and particle surface group density. The influence of direction of motion on conductive pulses was consistent with concentration polarization of an ion selective pore. Biphasic pulses were also seen to affect conventional TRPS particle size measurements.  Finally, size distribution broadening due to varying particle trajectories was investigated. Pulse size distributions for monodisperse particles became broader when the pore size was increased and featured two distinct peaks. Relatively large pulses are produced by particles with trajectories passing near to the edge of the pore. Other experiments determined that pulse size distributions are independent of applied voltage but broaden with increasing pressure applied across the membrane.</p>

scholarly journals Pore Size and Bulk Density as Mechanical Soil Factors Impeding Root Development

1969 ◽  
Vol 44 (1) ◽  
pp. 40-44
Author(s):  
M. A. Lugo-López
Keyword(s):  
Pore Size ◽  
Bulk Density ◽  
Root Development ◽  
Clay Soils ◽  
Combined Effects ◽  
Soil Horizons ◽  
Soil Factors ◽  
High Bulk Density ◽  
Guinea Grass ◽  
High Bulk

Measurements of pore size and bulk density for seven clay soils are reported in this paper as related to observations on root development under field conditions of Para, Guinea, and Bermuda grasses. The combined effects of high bulk density and predominantly small pores apparently reduce root development in Para and Bermuda. Guinea grass, a dryland forage, is able to send roots through relatively dense soil horizons with high microporosity. This might explain, at least in part, the drought tolerance of this grass.

Oligo-ethylene-glycol based thin-film composite nanofiltration membranes for effective separation of mono-/di-valent anions

2019 ◽  
Vol 7 (4) ◽  
pp. 1849-1860 ◽  
Author(s):  
Dan Ren ◽  
Xiao-Tian Bi ◽  
Tian-Yin Liu ◽  
Xiaolin Wang
Keyword(s):  
Thin Film ◽  
Ethylene Glycol ◽  
Pore Size ◽  
Aromatic Polyamide ◽  
Nanofiltration Membranes ◽  
Film Composite ◽  
Thin Film Composite ◽  
Effective Separation

A novel oligo-ethylene-glycol-containing semi-aromatic polyamide NF membrane with precise pore size shows effective separation for mono-/divalent anions.

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